This invention relates to a low cost brush assembly for electric motors. More particularly, it relates to such an electric brush assembly which has the multiple advantages of ease and economy of fabrication, assembly and installation in a motor housing.
As is well known, armature wound motors having segmented commutators must have conducting brushes for providing electrical connection to the armature windings. These brushes are ordinarily of solid graphite material which is spring pressed into conductive engagement with a cylindrical commutator, or slip ring. Provision must be made for containing these brushes in the motor housing generally radially disposed to the segmented commutator or slip rings. Provision must also be made for an external conducting link from the brushes to power terminals, or to the rest of the motor circuit. Ordinarily the brushes are contained in a separate motor brush assembly which, when inserted into the motor housing, serves the following purposes: it aligns the brush with the commutator; it provides a spring bias to hold the brush in conductive engagement against the commutator; it provides a continuous circuit connection to the brush; it provides a terminal for the connection of the brush into the motor circuit; and it insulates the brush from the motor housing and other motor parts. In the prior art, these motor brush assemblies have often taken complex forms having many separate parts which had to be assembled, including screws, machine bored pieces, and other parts requiring costly close tolerance machining. Often the metallic brush holders have required complex metal forming techniques. Consequently, the prior art motor brush assemblies have entailed high costs of fabrication, assembly and installation.